Process for the preparation of bisarylalkyl ethers

ABSTRACT

A process for preparing a substituted styrene by reacting a bisarylalkyl ether in the presence of an acid catalyst is disclosed. The process is preferably used for the preparation of 4-acetoxystyrene from 4,4&#39;-(oxydiethylidene)bisphenol diacetate and 4-methoxystyrene from 4,4&#39;-(oxydiethylidene)bisphenol dimethyl ether. A process for preparing a bisarylalkyl ether by reacting a corresponding arylalkanol in the presence of an acid catalyst is also disclosed.

This is a division of application Ser. No. 07/701,407 filed May 14,1991.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to the field of substituted styrenes and,more particularly, to a process for the preparation thereof frombisarylalkyl ethers and a process for the preparation of suchbisarylalkyl ethers from arylalkanols. Still more particularly, thepresent invention discloses a method of preparing 4-acetoxystyrene and4-methoxystyrene from 4,4'-(oxydiethylidene)bisphenol diacetate, and4,4'-(oxydiethylidene)bisphenol dimethyl ether, respectively.Furthermore, the present invention discloses a method of preparing4,4'-(oxydiethylidene)bisphenol diacetate and4,4-(oxydiethylidene)bisphenol dimethyl ether from4-acetoxyphenylmethylcarbinol and 4-methoxyphenylmethylcarbinol,respectively.

BACKGROUND OF THE INVENTION

Substituted styrenes are known compounds which are used in theproduction of photoresists, adhesives, coating compositions,pharmaceuticals, ultraviolet-absorbing sunscreen agents and other likecompounds. More particularly, they are used as intermediate monomers forthe production of polymers used for the preparation of said compounds.

A well known substituted styrene compound is 4-acetoxystyrene. Themonomer 4-acetoxystyrene is a stable monomer which can be readilypolymerized and copolymerized to low, medium and high molecular weightpolymers. The monomer readily polymerizes in solution, suspension,emulsion or bulk using well-known free radical catalysts such as, forexample, the peroxide and azo compounds. Such polymerization can takeplace in the absence of comonomers whereby the resultant product is ahomopolymer or in the presence of comonomers whereby the resultantproduct is a copolymer. Examples of processes used for the production ofhomopolymers or copolymers of 4-acetoxystyrene are the processesdisclosed in U.S. Pat. Nos. 4,822,862, 4,912,173 and 4,962,147. Otherwell-known processes can also be used.

In the case of copolymerization, the most commonly used comonomer isstyrene. Other comonomers include vinyltoluene; alpha-methylstyrene;ortho-, meta-, and para- cloro- and bromostyrene; the diene monomerssuch as butadiene, the acrylate and methacrylate ester monomers such asmethyl acrylate, ethyl acrylate, butyl acrylate, butyl methacrylate and2-ethylhexyl acrylate; acrylonitrile; methacrylonitrile; thepolymerizable acids such as acrylic acid, methacrylic acid, maleic acid,fumaric acid and the like; and the allyl ester comonomers described inU.S. Pat. No. 4,877,843. The homopolymers and the copolymers of4-acetoxystyrene can be hydrolyzed to produce homopolymers andcopolymers of 4-hydroxystyrene which are well-known compositions used inthe manufacturing of metal treatment compositions, photoresists, epoxyresins and epoxy resin curing agents. Processes for the conversion ofhomopolymers and copolymers of 4-acetoxystyrene to homopolymers andcopolymers of 4-hydroxystyrene are disclosed in U.S. Pat. Nos.4,678,843, 4,689,371, 4,822,862, 4,857,601, 4,877,843, 4,898,916,4,912,173, and 4,962,147.

Several methods have been developed for the production of the monomer4-acetoxystyrene. Corson, et al., Preparation of Vinylphenols andIsopropenylphenols, 23 J. Org. Chem. 544-549 (1958), discloses a processfor making 4-acetoxystyrene from phenol. According to the process,phenol is acylated to 4-hydroxyacetophenone which is then acetylated to4-acetoxyacetophenone. The latter compound is hydrogenated to4-acetoxyphenylmethylcarbinol, which is, then, dehydrated to4-acetoxystyrene. Another process for the preparation of4-acetoxystyrene is disclosed in copending U.S. patent application Ser.No. 07/548,170, now U.S. Pat. No. 5,041,614, which is incorporatedherein and is made part hereof by reference. In that process,4-acetoxyphenylmethylcarbinol is dehydrated in the presence of aceticanhydride and an acid catalyst to form 4-acetoxystyrene. The compound4-acetoxyphenylmethylcarbinol is sometimes referred to herein forbrevity and convenience as "APMC."

Copending U.S. patent application Ser. No. 07/598,510, now U.S. Pat. No.5,151,546, discloses methods of preparing APMC. One method involvesheating 4-acetoxyacetophenone at a temperature of from about 54° C. toabout 120° C. and at a pressure of about 14.7 psig to about 5000 psig inthe presence of at least a stoichiometric amount of hydrogen and acatalyst selected from the group consisting of Pd/C or activated nickelin the absence of a solvent. Another method involves the hydrogenationof 4-acetoxyacetophenone with a suitable reagent such as NaBH₄, lithiumaluminum hydride, hydrogen and diisobutyl aluminum hydride in thepresence of a solvent.

Another method of preparing 4-acetoxystyrene is disclosed in copendingU.S. patent application Ser. No. 07/598,510 which is incorporated hereinand is made part hereof by reference. APMC is dehydrated in the presenceof a dehydrating agent such as KHSO₄, alumina, titania, silica gel andmineral acids. The reaction is carried out under substmosphericconditions at a temperature in the range of 85° C. to 300° C. for about0.2 to about 10 minutes.

Examples of other substituted styrene derivatives are disclosed in U.S.Pat. Nos. 4,868,256; 4,868,257; 4,933,495; 4,927,956 and 4,965,400. U.S.Pat. Nos. 4,868,256; 4,868,257 and 4,933,495 disclose methods forproducing substituted styrenes and, more particularly, 3-mono or3,5-disubstituted acetoxystyrene by dehydrating 1-(3'-mono or3',5'-disubstituted-4'-acetoxyphenyl) ethanol with an acid or a base andhydrolyzing said product to produce 3-mono or 3,5-disubstitutedhydroxystyrene. The substituents are selected from the group consistingof Cl, Br, I, NO₂, NH₂, SO₃ H or C₁ -C₁₀ alkyl. Furthermore, thosepatents disclose a method of producing 3-bromo-4-acetoxy-5-methylstyrenefrom 1-(3'-bromo-4'-acetoxy-5'-methylphenyl)ethanol.

U.S. Pat. No. 4,927,956 discloses 3,5-disubstituted-4-acetoxystyrenewherein the substitution is independently C₁ to C₁₀ alkyl or alkoxy oramino; and substituted 4-hydroxy- and 4-acetoxystyrene compounds whereinthe substitutes in the 2,3 and 6- positions are independently hydrogen,alkyl, alkoxy or halogen and the substitute in the 5-position ischlorine or bromine.

U.S. Pat. No. 4,965,400 is directed to a method of preparing3,5-disubstituted-4-acetoxystyrene by dehydrating1-(3',5'-disubstituted-4'-acetoxyphenyl)ethanol wherein each of the3,5-substitutions are independently C₁ to C₁₀ alkyl or alkoxy, amino orhalogen. The reaction is carried out in the presence of an aciddehydrating agent.

Although several methods were employed in the past for the preparationof substituted styrenes, none of those methods involved the preparationof such substituted styrenes from bisarylalkyl ethers such as4,4'-(oxydiethylidene)-bisphenol diacetate or4,4'-(oxydiethylidene)bisphenol dimethyl ether.

4,4'-(oxydiethylidene)bisphenol diacetate which is otherwise identifiedas bis (4-acetoxyphenylmethylcarbinol) ether is sometimes referred toherein for brevity and convenience as "APMC-Ether." The compound4,4'-(oxydiethylidene)bisphenol dimethyl ether which is otherwiseidentified as (4-methyoxyphenylmethylcarbinol) ether is sometimesreferred to herein for brevity and convenience as "MPMC-Ether."

APMC-Ether is a compound isolated from a species of mushrooms asdisclosed in F. Bohlmann et al., Phytochemistry 18(8), 1403 (1979).Furthermore, APMC-Ether is formed as an impurity in the acid catalyzeddehydration of APMC to 4-acetoxystyrene monomer and in the thermaltreatment of APMC during its purification.

In the past, there were no uses for APMC-Ether, Accordingly, APMC-Etherremoved from mixtures containing it as an impurity required disposal inlandfills or similar disposal sites thereby giving rise to economic andenvironmental burdens. According to the present invention, APMC-Ether isused to produce 4-acetoxystyrene whereby the aforesaid economic andenvironmental burdens are eliminated.

In addition to disclosing a method of preparing substituted styrenederivatives from bisarylalkyl ethers, the present invention discloses amethod of preparing such bisarylalkyl ethers from correspondingarylalkanols. Such method is preferably used for the preparation ofAPMC-Ether from APMC and for the preparation of MPMC-Ether from4-methoxyphenylcarbinol which is sometimes referred to herein forbrevity and convenience as "MPMC." No such method was disclosed by theprior art.

These and other advantages of the present invention will become apparentfrom the following description.

SUMMARY OF THE INVENTION

A bisarylalkyl ether such as APMC-Ether or MPMC-Ether is heated in thepresence of an acid catalyst to produce a substituted styrene such as4-acetoxystyrene or 4-methoxystyrene, respectively. The reactant whichis in the liquid phase is heated to a temperature of about 160° C. toabout 230° C. to convert the bisarylalkyl ether to the substitutedstyrene by cleavage and dehydration. The reaction is preferably carriedout under subatmospheric conditions to effect the immediate vaporizationand removal of the substituted styrene product from the reactor toprevent the polymerization of such product. The reaction is carried outpreferably in the presence of a free radical inhibitor which inhibitsthe free radical polymerization of the substituted styrene product. Inthe case of the preparation of 4-acetoxystyrene from APMC-Ether, thereaction is preferably carried out also in the presence of aceticanhydride to prevent the hydrolysis of 4-acetoxystyrene to4-hydroxystyrene.

A method of preparing a bisarylalkyl ether from a correspondingarylalkanol through the condensation of the arylalkanol in the presenceof an acid catalyst is also disclosed. Such method is preferably usedfor the preparation of APMC-Ether from APMC and for the preparation ofMPMC-Ether from MPMC. The arylalkanol reactant is heated to atemperature of about 80° C. to about 120° C. in the presence of thecatalyst. The reaction is preferably carried out under subatmosphericpressure to effect the rapid removal of the water coproduct of thereaction. Such removal causes an increase in the yield and selectivityto the bisarylalkyl ether.

DETAILED DESCRIPTION OF THE INVENTION (a) Preparation of SubstitutedStyrenes from Bisarylalkyl Ethers

According to the present invention, a process for the production of asubstituted styrene is disclosed by heating a bisarylalkyl ether in thepresence of an acid catalyst. One equivalent of the bisarylalkyl etheris cleaved and dehydrated to produce two equivalents of substitutedstyrene. The substituted styrene produced in accordance of the presentinvention is of the formula: ##STR1## wherein R₁ is ##STR2## --O--CH₃,--O--CH₂ --CH₃, halogen or NO₂ ; and R₂, R₃, R₄ and R₅ are independentlyhydrogen, halogen or C₁ -C₄ alkyl.

The reactant bisarylalkyl ether is of the formula (Formula 2), ##STR3##wherein R₁ is ##STR4## --O--CH₃, --O--CH₂ --CH₃, halogen or NO₂ ; andR₂, R₃, R₄ and R₅ are independently hydrogen, halogen, or C₁ -C₄ alkyl.

The reactant bisarylalkyl ether in its liquid phase is fed to a reactor.Therein, in the presence of the acid catalyst, it is heated to atemperature which is sufficiently high to effect the cleavage anddehydration of the reactant to form the substituted styrene butsufficiently low to minimize the tendency of the components of thereaction mass for polymerization. Accordingly, the reaction is carriedout at temperatures in the range of about 120° C. to about 230° C. and,preferably, in the range of about 160° C. to about 220° C. The reactionmass is continuously stirred by well known stirring means to maintainthe homogeneity thereof.

Because the substituted product readily polymerizes under thetemperature conditions encountered in the reaction, it is preferred thatthe product be removed immediately from the reaction mass viaevaporation. Accordingly, the reaction is carried out undersubatmospheric conditions, preferably in the range of about 0.5 mm Hg toabout 100 mm Hg, to effect the immediate vaporization and removal of theproduct from the reaction mass. The vaporized product is cooled andcondensed in a condenser and is collected as a liquid product in anoverhead receiver.

The conversion of the bisarylalkyl ether to substituted styrene inaccordance with the present invention is relatively fast. In the case ofthe conversion of APMC-Ether, for example, the conversion typicallytakes place in about less than one second to about 15 minutes dependingon feed rate to the reactor, mixing conditions and temperature.

The reaction may be carried out in a batch mode, a continuous mode or acombination thereof such as a continuous fed-batch mode. In thecontinuous fed-batch mode, reactant and catalyst are continuously fed tothe reactor, the substituted styrene product is continuously removed byevaporation and the residue and the catalyst are allowed to build up inthe reactor until the end of the cycle.

Any one of the acid catalysts may be used to carry out the reaction ofthe present invention. Such catalysts include, but are not limited to,phosphoric acid, p-toluenesulfonic acid, methanesulfonic acid, ammoniumbisulfate and potassium bisulfate. The amount of catalyst requiredvaries from catalyst to catalyst. In all instances, however, the amountis very small as compared to the amount of reactant. In the case of theconversion of APMC-Ether to 4-acetoxystyrene, for example, the amount ofcatalyst is usually less that one (1) mole of catalyst per 100 moles ofreactant APMC-Ether.

In accordance with the present invention, the reaction is typicallycarried out stoichiometrically as follows (Reaction 1): ##STR5## whereinR₁ is ##STR6## --O--CH₃, --O--CH₂ --CH₃, halogen or NO₂ ; and R₂, R₃, R₄and R₅ are independently hydrogen or C₁ -C₄ alkyl.

In the case of converting, a bisarylalkyl ether of Formula 2 wherein R₁is ##STR7## (acetoxy) to a corresponding acetoxy-substituted styrene,although the reaction can be carried out in the absence of aceticanhydride, it is preferred that acetic anhydride be fed to the reactortogether with the reactant acetoxy-containing bisarylalkyl ether toprevent the hydrolysis of the acetoxy-containing substituted styreneproduct to a corresponding hydroxy-containing compound. For example, inthe case of APMC-Ether conversion to 4-acetoxystyrene, it is preferredthat acetic anhydride be fed to the reactor together with the reactantAPMC-Ether to prevent the hydrolysis of the 4-acetoxystyrene product to4-hydroxystyrene. The amount of acetic anhydride may be as high as aboutfive (5.0) moles of acetic anhydride per one (1) mole of reactantAPMC-Ether with the preferred amount being 0.05 moles of aceticanhydride per one (1) mole of reactant APMC-Ether. When the reaction iscarried out in the absence of acetic anhydride, one (1) mole ofAPMC-Ether is converted to two (2) moles of 4-acetoxystyrene and one (1)mole of water in a reaction represented stoichiometrically as follows:##STR8##

When the reaction is carried out in the presence of acetic anhydride theAPMC-Ether reacts stoichiometrically with the acetic anhydride inaccordance with the following reaction (Reaction 3): ##STR9##

If the amount of a cetic anhydride available for the reaction is lessthan the stoichiometric amount shown in Reaction 3, i.e., one (1) moleof acetic anhydride per one (1) mole of APMC-Ether, the APMC-Ether whichis not converted by Reaction 3 is converted by Reaction 2.

In order to minimize the free radical polymerization of the substitutedstyrene product such as 4-acetoxystyrene or 4-methoxystyrene, it ispreferred that a free radical inhibitor be used in the reaction toinhibit polymerization. Any known inhibitors such as phenothiazine,t-butyl catechol or the like that effect such quenching may be used. Theuse of the inhibitor, however, is not necessary for the reaction of thepresent invention to be carried out.

(b) Preparation of Bisarylalkyl Ethers from Arylalkanols

As discussed in the Background of the Invention section hereof, thepresent invention discloses a method of preparing bisarylalkyl etherfrom corresponding arylalkanols. The reaction is represented as follows(Reaction 4): ##STR10## wherein R₁ is ##STR11## --O--CH₃, --O--CH₂--CH₃, halogen or NO₂ ; and R₂, R3, R4 and R₅ are independentlyhydrogen, halogen or C₁ -C₄ alkyl. The method is preferably used for theconversion of APMC to APMC-Ether and for the conversion of MPMC toMPMC-Ether.

The reactant arylalkanol is fed as liquid to a reactor together with anacid catalyst. The reactant and the catalyst are thoroughly mixed andheated to a temperature in the range of about 80° C. to about 120° C.which is sufficiently high to initiate and complete the condensationreaction shown as Reaction 4. At lower temperatures, the reaction isvery slow and, at higher temperatures, the bisarylalkyl ether productsuch as AMPC-Ether or MPMC-Ether tends to decompose.

In order to increase the yield of arylalkanol to bisarylalkyl ether, itis preferred that the water product of the reaction be immediatelyremoved. Accordingly, the reaction is carried out under subatmosphericconditions in the range of about 0.1 mm Hg to about 760 mm Hg toaccomplish the immediate removal of the water through vaporization. Thepreferred pressure is in the range of about 0.1 mm Hg to about 50 mm Hgand the most preferred pressure is in the range of about 0.1 mm Hg toabout 2 mm Hg.

An organic solvent may also be used to remove the water extensively andsatisfactorily by codistilling the water with the solvent. The solventmay be recirculated to the reactor for further use. Examples of suchsolvent include, but are not limited to toluene and1,2,4-trimethylbenzene.

Any acid catalyst may be used to carry out the reaction. Strong acidcatalysts, however, such as sulfuric acid tend to promote the formationof polymers and other undesirable byproducts. Accordingly, weak acidcatalysts are preferred. Examples of such catalyst include, but are notlimited to potassium bisulfate, phosphoric acid, p-toluenesulfonic acidand ammonium bisulfate. The most preferred acid catalysts are thosehaving a dissociation constant similar to the dissociation constant ofpotassium bisulfate, (pKa≃2 (relative to water)).

The amount of catalyst required varies depending on the reactionconditions and the type of the catalyst. In the case of potassiumbisulfate with the reaction being carried at about 100° C., thepreferred amount of catalyst is about 8 to about 9 weight percent of thetotal charge to the reactor.

The reaction is relatively slow and the reaction time is in the range ofabout 0.5 hours to about 8.0 hours depending on the reaction conditions,the catalyst and other factors. In a typical reaction wherein APMC isused to produce APMC-Ether in the presence of about 9 weight percentpotassium bisulfate catalyst at about 100° C. and 0.25 mm Hg, thereaction time is from about 1.0 to about 4.0 hours.

Because the reaction time is relatively slow, the reaction is preferablycarried out in a batch mode. A continuous mode, however, whereinreactants and catalyst are slowly fed to the reactor and products areslowly removed therefrom may be used.

The following examples further illustrate the invention but are not tobe construed as limitations on the scope of the invention contemplatedherein. Examples 1-3 demonstrate the conversion of APMC-Ether to4-acetoxystyrene. Example 4 illustrates the conversion of MPMC-Ether to4-methoxystyrene. Examples 5-7 illustrate the conversion of APMC toAPMC-Ether. Example 8 illustrates the converstion of MPMC to MPMC-Ether.All calculations of conversions, selectivities and yields are based onmoles of the compounds involved.

EXAMPLE 1

A flask heated by hot oil was fitted with a chilled water overheadcondenser, a thermowell with a thermocouple, an overhead stirrer and avacuum pump. Crude APMC-Ether (20 grams) containing 78.2 weight percentAPMC-Ether, 7.2 weight percent APMC and 3.9 weight percent4-acetoxyphenylmethylcarbinol acetate (sometimes referred to herein as"APMC-Acetate") was mixed in another flask with six (6.0) grams ofacetic anhydride. Phosphoric acid (0.022 grams) having a concentrationof 85 weight percent that corresponds to 0.32 moles of pure phosphoricacid per 100 moles of APMC-Ether was added to said mixture. Theresultant mixture was fed to the hot flask at a rate of 1.2 grams perminute. The hot oil temperature was maintained at about 220° C. to about230° C. and the reaction mass temperature in the hot flask wasmaintained at about 180° C. to about 200° C. The vacuum pump maintaineda vacuum in the flask at about 80 mm Hg. 4-acetoxystyrene and aceticacid were produced in the hot flask.

The vacuum conditions caused the 4-acetoxystyrene and the acetic acidproducts to vaporize in the flask as soon as they were formed togetherwith unreacted acetic anhydride. The vapors were condensed in theoverhead condenser and collected in an overhead receiver. The residueand the catalyst were allowed to build up in the hot flask and werediscarded after the cycle was completed.

At the end of the reaction, the total amount of residue removed from theflask was 9.3 grams and the product collected in the overhead receiverwas 15.6 grams. The overhead product contained 54.6 weight percent4-acetoxystyrene. The conversion of the crude APMC-Ether was 99.6percent with the selectivity to 4-acetoxystyrene being 51.2 percentcorresponding to a 4-acetoxystyrene yield of 51.0 percent. The yieldcalculation was determined on the basis of two moles of 4-acetoxystyrenebeing obtained per one mole of APMC-Ether and one mole of4-acetoxystyrene being obtained per mole of APMC and APMC-Acetate.

EXAMPLE 2

A flask heated by hot oil was fitted with a chilled water overheadcondenser, a thermowell with a thermocouple, an overhead stirrer and avacuum pump. Crude APMC-Ether (20.0 grams) containing 78.2 weightpercent APMC-Ether, 7.2 weight percent APMC and 3.9 weight percentAPMC-Acetate was mixed in another flask with acetic anhydride (6.0grams) and p-toluenesulfonic acid (0.027 grams). The resultant mixturewas fed to the hot flask at a rate of 1.2 grams per minute. The hot oiltemperature was maintained at about 220° C. to about 230° C. and thereaction mass temperature in the hot flask was maintained at about 180°C. to about 20020 C. The vacuum pump maintained a vacuum in the flask atabout 80 mm Hg. The vacuum conditions caused the 4-acetoxystyrene andthe acetic acid products to vaporize from the flask as soon as they wereformed together with unreacted acetic anhydride. The vapors werecondensed in the overhead condenser and collected in an overheadreceiver. The residue and the catalyst were allowed to build up in thehot flask and were discarded after the cycle was completed.

At the end of the reaction, the total amount of residue removed from theflask was 3.7 grams and the product collected in the overhead receiverwas 21.4 grams. The overhead product contained 62.9 weight percent4-acetoxystyrene. The conversion of the crude APMC-Ether was 98.0percent with the selectivity to 4-acetoxystyrene being 82.3 percent andcorresponding to a 4-acetoxystyrene yield of 80.6 percent. The yieldcalculation was determined as described in Example 1.

EXAMPLE 3

A flask heated by hot oil was fitted with a chilled water overheadcondenser, a thermowell with a thermocouple, an overhead stirrer and avacuum pump. Crude APMC-Ether (20.0 grams) containing 76.7 weightpercent APMC-Ether, 1.5 weight percent APMC and 4.6 weight percentAPMC-Acetate was mixed in another flask. Ammonium bisulfate (0.03 grams)corresponding to 0.45 moles of ammonium bisulfate per 100 moles ofAPMC-Ether was added to said mixture. The resultant mixture was fed tothe hot flask at a rate of 1.2 grams per minute. The hot oil temperaturewas maintained at about 220° C. to about 230° C. and the reaction masstemperature in the hot flask was maintained at about 180° C. to about200° C. The vacuum pump maintained a vacuum in the flask at about 80 mmHg. The vacuum conditions caused the 4-acetoxystyrene and acetic acidproducts to vaporize from the hot flask as soon as they were formedtogether with unreacted acetic anhydride. The vapors were condensed inthe overhead condenser and collected in an overhead receiver. Theresidue and the catalyst were allowed to build up in the hot flask andwere discarded after the cycle was completed.

At the end of the reaction, the total amount of residue removed from theflask was 2.4 grams and the product collected in the overhead receiverwas 23.2 grams. The overhead product contained 65.3 weight percent4-acetoxystyrene. The conversion of the crude APMC-Ether was 97.0percent with the selectivity to 4-acetoxystyrene being 100 percent andcorresponding to a 4-acetoxystyrene yield of 97.0 percent. The yieldcalculation was determined as described in Example 1.

EXAMPLE 4

A flask was fitted with a chilled water overhead condenser, a thermowellwith a thermocouple, a magnetic stirrer and a vacuum pump. MPMC-ether(9.6 grams, 33.6 mmoles) was mixed with methanesulfonic acid (0.0062grams, 0.065 mmole) and the mixture was added to the flask. The flaskwas heated to 140° C. with a hot oil bath and a vacuum was maintained at3 mm Hg. The reaction was complete in 20 minutes. The product4-methoxystyrene was distilled over as a colorless liquid. Seven (7.0)grams of product were obtained corresponding to a yield of 77 percent.

EXAMPLE 5

A one liter, three-necked flask was fitted with thermowell, a heatingmantle, a mechanical stirrer and a Dean-Stark trap. A chilled watercondenser, fitted with a pressure equalizing dropping funnel and avacuum port was placed on top of the trap. The flask was charged with100.1 grams of APMC, 297.2 grams of 1,2,4-trimethylbenzene and 38.1grams (8.8 weight percent) potassium bisulfate. The reaction was heatedto reflux at 90° C. under vacuum conditions (143 mm Hg). The reactionmass was continuously stirred for good mixing. After 100 minutes, thereaction was allowed to cool and was gravity filtered. The filtrate wasshaken with 10.0 grams of sodium bicarbonate and was allowed to standfor one hour. The mixture was filtered and the filtrate was concentratedon a rotary evaporator at 1.0 mm Hg. The oil was shaken with an equalweight of petroleum ether to remove residual trimethylbenzene. Theproduct was allowed to phase separate and the petroleum ether wasstripped on the rotary evaporator at 143 mm Hg. Treatment with petroleumether was repeated and, after rotovapping, the residual oil was analyzedby gas chromatography. The yield of APMC-Ether, based on APMC, was about51 percent.

EXAMPLE 6

A three liter three-necked flask was fitted with a thermowell, a heatingmantle, a mechanical stirrer and a Dean Stark trap. A chilled watercondenser leading to a bubbler was placed on top of the trap. The flaskwas charged with 250.4 grams of APMC, 742.4 grams of toluene and 94.7grams (8.7 weight percent) of potassium bisulfate. The reaction washeated to reflux at 111° C. After five (5.0) hours the reaction wassampled for gas chromatography analysis. The reaction was carried outunder atmospheric pressure conditions (760 mm Hg). The conversion ofAPMC was 79.4 percent and the selectivity to APMC-Ether based on APMC63.7 percent corresponding to a yield of APMC-Ether based on APMC of 51percent.

EXAMPLE 7

A 100 milliliter two-necked flask was fitted with a thermowell, amagnetic stirrer and a vacuum port. The flask was charged with 59.35grams of APMC and 5.69 grams (8.7 weight percent) of potassiumbisulfate. The reaction mass was heated on an oil bath at 100° C. under0.250 mm Hg. After 2.0 hours, the reaction was sampled forchromatography analysis. The yield of APMC-Ether, based on APMC, wasabout 84 percent.

EXAMPLE 8

A 100 milliliter flask equipped with a condenser, a magnetic stirrer anda hot-oil bath was charged with 4-methoxyphenylmethylcarbinol (MPMC)(50.0 grams) and p-toluenesulfonic acid (0.066 grams). The reactionmixture was heated to 80° C. and was stirred for 16 hours. The reactionmixture was then cooled to room temperature. Then it was dissolved inethyl acetate (250 milliliters) and was washed with water three timeswith 250 milliliters of water each time. The organic layer was separatedfrom the mixture and was dried over anhydrous magnesium sulfate. Then,it was concentrated on a rotary evaporator. The product was analyzed bygas chromotography which showed it to contain MPMC-Ether (70 percent),MPMC (17 percent) and 4-methoxystyrene (10 percent). This corresponds toan MPMC conversion of 83 percent. Distillation of this mixture underreduced pressure afforded pure MPMC-Ether.

While the invention is described with respect to specific embodiments,modifications thereof can be made by one skilled in the art withoutdeparting from the spirit of the invention. The details of saidembodiments are not to be construed as limitations except to the extentindicated in the following claims.

What is claimed is:
 1. A process, comprising the steps of:contacting anarylalkanol of the formula ##STR12## with an acid catalyst; and heatingthe arylalkanol catalyst mixture to form a bisarylalkyl ether of theformula ##STR13## wherein R₁ is ##STR14## --O--CH₃, --O--CH₂ --CH₃,halogen or NO₂ ; and R₂, R3, R4 and R₅ are independently hydrogen,halogen or C₁ -C₄ alkyl.
 2. The process according to claim 1 wherein theheating step further forms water.
 3. The process according to claim 2wherein there is included the step of removing the water.
 4. The processaccording to claim 2 wherein there is included the steps of:contactingthe water with an organic solvent; and codistilling the water and theorganic solvent.
 5. The process according to claim 2 wherein there isincluded the step of vaporizing the water.
 6. The process according toclaim 2 wherein there is included the step of providing a pressure whichis sufficiently low to effect the vaporization of the water.
 7. Theprocess according to claim 1 wherein the acid catalyst is a weakcatalyst.
 8. The process according to claim 1 wherein the acid catalystis potassium bisulfate.
 9. The process according to claim 1 wherein theheating is at a temperature of about 80° C. to about 120° C.
 10. Theprocess according to claim 2 wherein there is included the step ofmaintaining a subatmospheric pressure which is sufficiently low toeffect the vaporization of the water.
 11. The process according to claim1 wherein the arylalkanol is 4-acetoxyphenylmethylcarbinol and thebisarylalkyl ether is 4,4'-(oxydiethylidene)bisphenol diacetate.
 12. Theprocess according to claim 1 wherein the arylalkanol is4-methoxyphenylmethylcarbinol and the bisarylalkyl ether is4-4'-(oxydiethylidene)bisphenol dimethyl ether.
 13. A process forproducing a bisarylalkyl ether of the formula ##STR15## comprising thesteps of: mixing an arylalkanol of the formula ##STR16## with an acidcatalyst; and subjecting the mixture to a temperature of about 80° C. toabout 120° C. wherein R₁ is ##STR17## --O--CH₃, --O--CH₂ --CH₃, halogenor NO; and R₂ ; R3, R4 and R₅ are independently hydrogen, halogen or C₁-C₄ alkyl.
 14. A method of preparing a bisarylalkyl ether of the formula##STR18## comprising the steps of: interacting an arylalkanol of theformula ##STR19## with an acid catalyst; and heating the mixture to atemperature which is sufficient to convert the arylalkanol to thebisarylalkyl ether and water, wherein R₁ is ##STR20## --O--CH₃, --O--CH₂--CH₃, halogen or NO₂ ; and R₂, R3, R4 and R₅ are independentlyhydrogen, halogen or C₁ -C₄ alkyl.